This invention relates in general to reaction chambers and relates more particularly to the supply of reactant gases to such chambers.
In the figures, each element indicated by a reference numeral will be indicated by the same reference numeral in every figure in which that element appears. The first digit of any two or three digit reference numerals indicates the first figure in which its associated element is presented.
To remain price competitive in integrated circuit fabrication it is important to increase continually the throughput of a wafer processing system. Batch processing systems have been used to increase throughput. However, in state of the art devices it is necessary to utilize single wafer processing systems to achieve the processing uniformity needed to achieve state of the art feature sizes. For equipment utilized to achieve state of the art linewidths it is particularly important to achieve as high a uniformity of processing across the wafer as possible.
As the feature size of integrated circuits shrinks and the size of wafers increases, it becomes increasingly important to accurately control the rates of various wafer processing steps to achieve process uniformity across the entire wafer. The uniformity obtained by all process steps, including all plasma processes and chemical vapor deposition processes, are affected by the distribution of process gases within the processing chamber. In many existing systems, process gases are injected into the processing chamber at a point that is remote from the wafer so that a uniform distribution of the gases is achieved before these gases reach the wafer. The wafer is typically located between the remote gas inlets and an exhaust port so that the reactant gases flow past the wafer. To further improve the uniformity of processing, many systems include the ability to rotate the wafer during processing to increase the uniformity of the time-averaged physical and chemical environment of the wafer during processing. However, to achieve improved process control it would be advantageous to have a greater degree of control over the distribution of gases within the reaction chamber than is now available.